JPH08244086A - Pressure detecting pin - Google Patents

Abstract

PURPOSE: To perform easily assembling work of a detecting pin by forming a detecting member of a cylindrical part, a top board with a pressure receiving part being brought into contact with a working part and a bottom plate into a sealed cylindrical body and adhering a strain gauge prepd. by arranging a metal foil resistance in a bridge circuit on a resin base on the inside face of this top board. CONSTITUTION: When a molten resin is injected and filled into a cavity 2, a resin pressure is worked on the apex of a rod part 24 with a small diameter forming a part of the shape of the cavity 2 and a working force F pushing down a working pin is worked. As the working part 25 of the base side of the working pin is brought into contact with a projected pressure receiving part 41 formed on the top board of a detecting member 36 stored in a base holder 26, this working force F pushes the top board through the pressure receiving part 41. A strain is generated thereby on the top board and this strain is detected by means of a metal foil resistance formed into a grating-like shape and an electric signal is transmitted to a monitor circuit through a bridge circuit to measure conversion loading and to detect the resin pressure in the cavity 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detecting pin attached to a cavity of a resin injection mold to detect pressure.

[0002]

2. Description of the Related Art Conventionally, as a pressure detecting pin attached to a cavity of a resin injection molding die of this type to detect pressure,
For example, there is that disclosed in Japanese Utility Model Publication No. 2-42434. What is disclosed in this publication is a pinhole defect detection pin having a rod portion 6 which is inserted into an insertion hole 3 formed in a resin injection molding die 1 and constitutes a cavity 2 formed on a die mating surface. 4, the detection pin 4 is a body portion 5 having a predetermined diameter.
The main body part 5 has a rod part 6 of small diameter that faces the cavity 2 and forms a part of its shape, and a pin body having a flange part 7 is provided on the base side, and Fitting portion 8 from the central portion toward the center of main body portion 5
The fitting portion 8 is provided with a detecting portion 10 connected to a connecting line 9 connected to a monitor circuit, and is attached to the inner wall surface of the fitting portion 8 so as to be attached to the fitting portion 8. 11 and the like are filled to fix the detection unit 10 to the inner wall surface of the fitting unit 8 and hermetically seal it.

[0003]

However, in this conventional detecting pin 4, the detecting portion 10 is attached to the inner wall surface of the fitting portion 8 formed in the main body portion 5 by the resin 11. It is fixed and sealed, but the same detection unit 1
If 0 is displaced with respect to the axis of the main body 5, the resin pressure may not be detected and reliability may be reduced. Therefore, there is a problem that production is troublesome.・ There was a problem that required a box. The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a pressure detection pin which is easy to assemble and has high reliability and which has a bridge circuit integrally incorporated therein.

[0004]

In order to solve the above technical problems, the present invention provides a small-diameter rod which is inserted into an insertion hole formed in a resin injection molding die to form a cavity formed in a die mating surface. A pressure detection pin having a bottom portion, the pressure detection pin comprising a base holder having a bottomed cylindrical shape for accommodating a detection member, and a main body portion having a small diameter rod portion at the tip and an operation portion on the base side. The detection member is composed of a cylindrical holder and a cap holder mainly having a cylindrical edge portion for accommodating the operating portion, and the top plate and the bottom plate having a cylindrical portion and a pressure receiving portion contacting the operating portion. While forming into an envelope, a strain gauge with a metal foil resistor arranged in a bridge circuit is attached to a resin substrate on the inner surface of the top plate, and the connection line connected to the bridge circuit is connected to the monitor circuit, The detection member is By the serial base holder and the cap holder is a pressure sensing pin is configured to be pressed and fixed.

[0005]

With the above-described structure, the present invention functions to enhance the workability and watertightness of the pressure detection pin, as well as the responsiveness and reliability.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a pressure detection pin 21 attached to a resin injection molding die, and FIG. 2 is a sectional view of the pressure detection pin 21. As shown, the pressure detection pin (hereinafter, simply referred to as a detection pin) 21 includes an operation pin 22, a base holder 26, a cap holder 31, and a detection member 36 installed in the base holder 26.

The operating pin 22 has a main body portion 23 having a predetermined diameter, a small diameter rod portion 24 having a predetermined length formed at the tip end side of the main body portion 23, and a base portion side of the main body portion 23. A circular trapezoidal actuating portion 25 that is slidably housed in the cap holder 31 is formed.

The base holder 26 has a detecting member 35.
Is formed into a bottomed tubular body by a bottom portion 27 and a tubular edge portion 28 in which the connection wire 44 can be inserted, and the inner diameter portion on the opening side is formed. A screw portion 30 that is screwed into the cap holder 31 is screwed on the.

Further, the cap holder 31 has the operating pin 2
The lower part of the tubular body 32 includes a tubular body 32 into which the second operating portion 25 is slidably fitted and a guide portion 33 having a guide hole 34 for slidably guiding the main body portion 23 of the operating pin 22. A screw portion 35 that is screwed into the screw portion 30 of the base holder 26 is screwed on the outer periphery.

Further, the detecting member 36 is a strain gauge type load cell, and the detecting member 36 is composed of a cylindrical portion 37, a top plate 38 and a removable bottom plate 39 which can be stored in the base holder 26 as shown in FIG. The pressure receiving portion 41 is formed in a convex shape at the center of the top surface of the top plate 38, and the strain gauge 42 is attached to the inner surface of the top plate 37. . This strain gauge 42 is a disc-shaped metal foil resistor R formed on a resin substrate 43, for example, which can be attached to the back surface of the top plate 38, as shown in FIG.
1, R2, R3, R4 are glued and connected to the bridge circuit,
The conductor wire d of the covered wire D of the connection wire 44 is connected between the metal foil resistors R1, R2, R3, R4, the strain gauge 41 is attached to the back surface of the top plate 38, and the connection wire 44 is the cylindrical portion 37. Further, the detection member 36 is formed by being pulled out to the outside in a state of being sealed by the sealing member 45 and fixing the bottom plate 39.

The detecting member 36 thus formed is housed in the base holder 26, the connecting wire 44 is pulled out from the groove 29, and the main body 23 of the operating pin 22 is inserted into the guide hole 33 of the cap holder 31. Then, the operating portion 25 is housed in the tubular body 32, and the base holder 26
The detection pin 21 is formed by screwing the screw portions 30 and 35 of the cap holder 31 with each other. Further, the operating portion 25 of the operating pin 22 in the state where the screw portions 30 and 35 are screwed together.
Is abutted against the pressure receiving portion 41 of the detection member 36, and the lower end edge of the cap holder 31 is abutted and fixed to the upper four circumferences of the detection member 36.

The detection pin 21 thus formed is inserted into the insertion hole 3 of the movable mold 1A of the resin injection molding mold 1 including the movable mold 1A and the fixed mold 1B as in the conventional case. The tip portion of the small-diameter rod portion 24 is provided so as to form a part of the shape of each cavity 2 formed on the mating surface. Further, the connection line 44 is connected to a monitor circuit (not shown).

When the molten resin is injected into the cavities 2 and filled in the detection pins 21 thus arranged in the respective cavities 2, the small-diameter rod portion 24 forming a part of the shape of the cavities 2. The resin pressure acts on the tip of the action pin F to actuate the action pin F to push the actuating pin 22 downward. This acting force F is received by the actuating portion 25 on the base side of the actuating pin 22 because the actuating portion 25 is in contact with the convex pressure receiving portion 41 formed on the top plate 38 of the detecting member 36 housed in the base holder 26. The top plate 38 is pressed via the portion 41. This allows
A strain is generated in the top plate 38, and the strain is sensed by the metal foil resistors R1, R2, R3, R4 formed in a lattice shape, an electric signal is sent to the monitor circuit by the bridge circuit, and the conversion load (pressure) is measured, The resin pressure in the cavity 2 can be detected. Therefore, if a specified resin pressure for the cavity 2 is set on the monitor circuit side and an external display for checking excess or deficiency is installed in relation to this, if the resin pressure is below the specified pressure, It is possible to detect that the product obtained is defective in filleting or sinking, and if excessive, there is a high possibility of defective burr, and by adjusting the injection pressure thereafter. It is possible to prevent the generation of defective products. In addition, the detection pin 2
Since the tip of the cavity 1 constitutes a part of the cavity 2 and is attached, it can be attached regardless of the shape and size of the cavity 2, and therefore the cavity 2 is most likely to be cut. By providing it in an easy position, it is possible to sufficiently fulfill its function.

In particular, the detection pin 21 is connected to the detection member 36.
A guide hole 34 through which an operating pin 22 including a bottomed cylindrical base holder 26 for accommodating a body and a main body 23 having a small diameter rod portion 24 at the tip and an operating portion 25 at the base side can be inserted.
And a cap holder 31 mainly having a tubular edge portion 28 for accommodating the operating portion 25, and the detection member 36 includes a tubular portion 37, a top plate 38 having a pressure receiving portion 41, and a bottom plate 39, which is a sealed tubular body. And a strain gauge 42 in which metal foil resistors R1, R2, R3, R4 are arranged in a bridge circuit are attached to a resin substrate 43 on the inner surface of the top plate 38 and connected to the bridge circuit. 44 is connected to a monitor circuit, and the detection member 36 is pressed and fixed by the base holder 31 and the cap holder 31. Therefore, since the detection member 36 is formed in a closed cylindrical body and the strain gauge 42 is attached,
It is easy to handle as a single part, and the detection pin 21
The assembly work can be facilitated to improve the work efficiency, and the watertight effect can be enhanced due to the sealed structure. In addition, the detection member 36 is the base holder 2
Since it is pressed and fixed by 6 and the cap holder 31, it is possible to prevent rattling and the like, and it is possible to remarkably reduce the dropout of the strain gauge 42 due to vibration and the like, the disconnection of the connecting wire 44, etc. It can be increased and durability can be improved.

[0015]

As described above, according to the present invention, since the detecting member is formed in the closed cylindrical body and the strain gauge is attached, it can be handled as a single part. This facilitates the work of assembling the detection pin and improves the work efficiency, and the watertight effect can be enhanced due to the sealed structure. Further, since the detection member is pressed and fixed by the base holder and the cap holder, rattling and the like can be prevented, and the strain gauge 42 can be prevented from coming off due to vibration or the like, and the disconnection of the connecting wire 44 can be significantly reduced. Responsiveness and reliability can be improved and durability can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view in which a pressure detection pin is attached to a resin injection molding die.

FIG. 2 is a sectional view of a pressure detection pin.

FIG. 3 is a sectional view of a detection member.

FIG. 4 is a perspective view of a strain gauge.

FIG. 5 is a cross-sectional view in which a conventional detection pin is attached to a resin injection molding die.

[Explanation of symbols]

 1 Resin Injection Mold 2 Cavity 3 Insertion Hole 21 Pressure Detecting Pin 22 Actuating Pin 23 Main Body 24 Small Diameter Rod 25 Actuating Part 26 Base Holder 27 Bottom 28 Cylindrical Edge 31 Cap Holder 32 Cylindrical 33 Guide 34 34 Guide Hole 36 Detection member 37 Cylindrical part 38 Top plate 39 Bottom plate 41 Pressure receiving part 42 Strain gauge 43 Resin substrate 44 Connection line R1, R2, R3, R4 Metal foil resistance

Claims (1)

[Claims] 1. A pressure detection pin having a small-diameter rod portion which is inserted into an insertion hole formed in a resin injection molding die and constitutes a cavity formed on a die mating surface, wherein the pressure detection pin is for detection. Cylindrical rim for accommodating the operating part, which has a guide hole through which an operating pin consisting of a bottomed cylindrical base holder for accommodating members and a main body having a small diameter rod part at the tip and an actuating part at the base side can be inserted And a cap holder whose main component is, and the detection member is formed into a sealed cylindrical body by a top plate and a bottom plate having a cylindrical portion and a pressure receiving portion that abuts the operating portion, and a resin is provided on the inner surface of the top plate. A strain gauge having a metal foil resistor arranged in a bridge circuit is attached to a substrate, and a connecting line connected to the bridge circuit is connected to a monitor circuit, and the detection member is pressed and fixed by the base holder and the cap holder. Pressure detection pin configured as below.